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sensible output from decimator, haven't tested on FSK yet

master
David 2020-08-18 17:46:08 +09:30
parent ec04e1601a
commit a1c31efcc2
1 changed files with 28 additions and 14 deletions
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42
src/rtl_fsk.c
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@ -230,6 +230,7 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
}
csdr_decimate_cc((float*)pmodembuf, csdr_in, CSDR_BUFSIZE, csdr_taps, csdr_padded_taps_length, csdr_factor,
&csdr_nout, &csdr_nin);
fwrite((float*)pmodembuf, sizeof(complexf), csdr_nout, (FILE*)ctx);
/* place resampled signal in modem input buf */
pmodembuf += csdr_nout;
nmodembuf += csdr_nout;
@ -245,19 +246,23 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
/* when we have fsk_nin() samples run demod ----------------------------- */
pmodembuf = modembuf;
//fprintf(stderr, "start demod loop -----\n");
while(nmodembuf >= fsk_nin(fsk)) {
// fprintf(stderr, " nmodembuf: %ld fsk_nin: %d\n", nmodembuf, fsk_nin(fsk));
prev_fsk_nin = fsk_nin(fsk); /* fsk_nin gets updated in fsk_demod() */
fsk_demod(fsk, bitbuf, pmodembuf);
pmodembuf += 2*prev_fsk_nin;
nmodembuf -= 2*prev_fsk_nin;
pmodembuf += prev_fsk_nin;
nmodembuf -= prev_fsk_nin;
assert(nmodembuf >= 0);
#ifdef TMPOUT
/* output demodulated bits */
if (fwrite(bitbuf, 1, fsk->Nbits, (FILE*)ctx) != (unsigned int)fsk->Nbits) {
fprintf(stderr, "Short write, bits lost, exiting!\n");
rtlsdr_cancel_async(dev);
}
if((FILE*)ctx == stdout) fflush((FILE*)ctx);
#endif
if (dashboard) {
/* update buffer of timing samples */
@ -266,7 +271,7 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
else
fprintf(stderr, "norm_rx_timing_log full!");
sample_counter += fsk_nin(fsk);
if (sample_counter > samp_rate) {
if (sample_counter > DEFAULT_MODEM_SAMPLE_RATE) {
/* one second has passed, lets send some dashboard information */
char buf[BUF_SZ];
char buf1[BUF_SZ];
@ -275,26 +280,33 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
int m, step, start, k;
float SfdB[NDFT];
sample_counter -= samp_rate;
sample_counter -= DEFAULT_MODEM_SAMPLE_RATE;
buf[0]=0;
/* Current magnitude spectrum Sf[] from freq estimator */
/* Limit spectrum to NDFT points */
step = fsk->Ndft/NDFT;
for(i=0, start=0; i<NDFT; i++, start+=step) {
/* Limit spectrum to NDFT points */
if (fsk->Ndft > NDFT) {
step = fsk->Ndft/NDFT;
Ndft = NDFT;
} else {
step = 1;
Ndft = fsk->Ndft;
}
for(i=0, start=0; i<Ndft; i++, start+=step) {
/* Sf[] array is linear magnitudes */
sum = 0.0;
for(k=0; k<step; k++)
sum += fsk->Sf[start+k];
SfdB[i] = 20.0*log10(sum);
SfdB[i] = 20.0*log10(sum+1E-6);
}
snprintf(buf1, BUF_SZ, "{"); strncat(buf, buf1, BUF_SZ);
snprintf(buf1, BUF_SZ, "\"SfdB\":["); strncat(buf, buf1, BUF_SZ);
for(i=0; i<NDFT; i++) {
for(i=0; i<Ndft; i++) {
snprintf(buf1, BUF_SZ, "%f",SfdB[i]); strncat(buf, buf1, BUF_SZ);
if(i<NDFT-1) { snprintf(buf1, BUF_SZ, ", "); strncat(buf, buf1, BUF_SZ); }
if(i<Ndft-1) { snprintf(buf1, BUF_SZ, ", "); strncat(buf, buf1, BUF_SZ); }
}
snprintf(buf1, BUF_SZ, "]"); strncat(buf, buf1, BUF_SZ);
@ -333,7 +345,7 @@ static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
}
/* copy left over modem saples to start of buffer */
memmove(modembuf,pmodembuf,nmodembuf*sizeof(COMP));
memmove(modembuf, pmodembuf, nmodembuf*sizeof(COMP));
if (bytes_to_read > 0)
bytes_to_read -= len;
@ -539,7 +551,8 @@ int main(int argc, char **argv)
{
int P = DEFAULT_MODEM_SAMPLE_RATE/Rs;
fsk = fsk_create_hbr(DEFAULT_MODEM_SAMPLE_RATE,Rs,M,P,FSK_DEFAULT_NSYM,FSK_NONE,100);
fprintf(stderr,"FSK Demod Fs: %d Rs: %3.1f kHz M: %d P: %d Ndft: %d\n", DEFAULT_MODEM_SAMPLE_RATE,
fprintf(stderr,"FSK Demod Fs: %5.1f kHz Rs: %3.1f kHz M: %d P: %d Ndft: %d\n",
(float)DEFAULT_MODEM_SAMPLE_RATE/1000,
(float)Rs/1000, M, P, fsk->Ndft);
}
{
@ -548,6 +561,7 @@ int main(int argc, char **argv)
fsk_upper = 4*Rs;
if (fsk_lower < 2000) fsk_lower = 2000;
if (fsk_upper < channel_width) fsk_upper = channel_width;
if (fsk_upper > DEFAULT_MODEM_SAMPLE_RATE/2) fsk_upper = DEFAULT_MODEM_SAMPLE_RATE/2;
fprintf(stderr,"Setting estimator limits to %d to %d Hz.\n", fsk_lower, fsk_upper);
fsk_set_freq_est_limits(fsk,fsk_lower,fsk_upper);
}